1. Field of the Invention
The present invention relates to golf clubs, and, more particularly, to a set of golf club irons having a transitioning hollow space.
2. Description of the Related Art
Iron type golf clubs generally include a front or striking face, a top line, and a sole. The front face interfaces with and strikes the golf ball. A plurality of score lines or grooves is positioned on the face to assist in imparting spin to the ball. The top line is generally configured to have a particular look to the golfer and to provide weight. The sole of the golf club is particularly important to the golf shot because it contacts and interacts with the ground during the golf shot.
In conventional sets of iron-type golf clubs, each club includes a shaft with a club head attached to one end and a grip attached to the other end. The club head includes a face for striking a golf ball. The angle between the face and a vertical plane is called the loft angle.
The set generally includes irons that are designated number 2 through number 9, and a pitching wedge. Other wedges, such as a lob wedge, a gap wedge, and a sand wedge, may be optionally included with the set. Each iron has a shaft length that usually decreases through the set as the loft for each club head increases from the long irons to the short irons. The length of the club, along with the club head loft and center of gravity location, impart various performance characteristics to the ball's launch conditions upon impact and determine the distance the ball will travel. Flight distance generally increases with a decrease in loft angle and an increase in club length. However, difficulty of use also increases with a decrease in loft angle and an increase in club length.
Iron-type golf clubs generally can be divided into two categories: blades and cavity backs. Blades are traditional clubs with a substantially uniform appearance from the sole to the top line, although there may be some tapering from sole to top line.
Since blade designs have a small sweet spot (that is, the area of the face that results in a desirable golf shot upon striking a golf ball), they are relatively difficult to use and are therefore typically only used by skilled golfers. However, since these designs are less forgiving than cavity backs, they allow a skilled golfer to work the ball and shape the golf shot as desired.
Cavity backs are modern designs that move some of the club mass to the perimeter of the club by providing a hollow or cavity in the back of the club, opposite the striking face. This produces a more forgiving club with a larger sweet spot. Moving weight to the perimeter also allows the size of the club face to be increased. The perimeter weighting created by the cavity also increases the club's moment of inertia, which is a measurement of the club's resistance to torque, for example the torque resulting from an off-center hit. Because of the increased moment of inertia and larger face area, these clubs are easier to hit than blades, and are therefore usable by less-skilled and beginner golfers.